This invention relates generally to: an improved system for making multi-site skin tests; new and improved components used in the system; and a method of using the system.
U.S. Pat. Nos. 5,738,108 and 5,792,071, which issued to Applicant and which are incorporated herein by reference, are directed to various components of a system including a multi-site skin-test device, a tray of reservoirs for holding allergenic extract, and a tray lid.
A test device, also referred to herein as an applicator, of such a system is depicted in FIG. 1. The test device 5, includes an elongated handle 6. Multiple inverted U-shaped limbs 7 extend outwardly and downwardly from the handle 6. Each limb 7 includes a horizontal bight section 8 attached approximately at its mid-point to the underside of the handle 6 and a pair of downwardly extending legs 10. The distal ends of legs 10 lie in approximately the same plane, and each end has skin puncturing points indicated generally at 12. For example, the points 12 may take the form of nine pressure-type sharp points clustered closely together to create a capillary effect between the points for holding liquid in the interstices or spaces between the points as disclosed in Kravitz U.S. Pat. No. 3,136,314. The disclosure of U.S. Pat. No. 3,136,314 is incorporated herein by reference. The cross-sectional size of the legs 10 does not appreciably exceed the cross-sectional size of the points 12.
The handle 6 includes a guide formation 13 that extends generally transversely to the handle 6. The guide formation 13 includes a vertically extending concave groove or recess 14. Preferably, the applicator 5 will be integrally molded, such as by injection molding, from a suitable plastic. It could be formed, however, from other materials by other methods. By injection molding the applicator 5 from a plastic, the cost of these units can be reduced to a point at which the applicators are disposable after a single use. The applicators 5, therefore, can be sterilized before shipment. A healthcare worker can then open the packages, use the sterilized applicators, and discard the applicators immediately after using them.
The system also includes a tray 30, depicted in FIG. 2, for use in accordance with such an applicator or test device 5. The tray 30 has an upper surface 35. Twenty-four reservoirs 33, which extend downwardly from surface 35, are arranged in a repeating pattern that corresponds to the patterns of the distal points 12 of the test device 5. The reservoirs are used for storing allergenic skin test solutions to be loaded onto the pointed ends 12 of the test device 5. The reservoirs 33 are grouped into three batteries, labeled A, B, and C, each including eight reservoirs.
Referring to FIG. 3, the eight reservoirs of a particular battery are labeled one through eight starting with the reservoir in the upper-right-hand corner and proceeding clockwise. As discussed in more detail in Applicant""s U.S. Pat. No. 5,792,071, the reservoirs 33 each have a semi-cylindrical upwardly extending interior half 23 and an opposite inclined side 24 that is generally semi-conical.
Referring again to FIG. 2, to help a system user quickly and accurately guide the pointed ends 12 properly into each of the reservoirs 33, each of the three batteries or sets of reservoirs 22 in the tray 30 is provided with an upright orienting pin 32. The orienting or guide formation 13 on the handle 6 of the test device 5 is co-operable with the guide or orienting pin 32. When the handle 6 of the test device 5 is inserted between the pair of upright parallel tabs 31 and the guide formation 13 of the handle is placed against the guide pin 32, the test device can then be lowered properly aligned with the battery of reservoirs. When the test device 5 is lowered in proper alignment, each vertical leg 10 will be oriented so that its pointed ends 12 will be directly over the bottom of a reservoir 33. Each pair of tabs 31 is located such that when the guide formation 13 on of the test device 5 engages an orienting pin 32 the vertical edges of the tabs 31 nearer to the pin 32 will be engaged by the horizontal portions of the limbs 7 nearest the pin 32. Thus, each pin 32, each guide formation 13, each pair of limbs 7 juxtaposed to the formation 13, and each pair of tabs 31 jointly cooperate to readily guide and orient each test device 5 with respect to a set of reservoirs 33.
Applicant""s U.S. Pat. No. 5,738,108 discloses including formations 34 on opposite sides along the bottom edge of the test device""s handle 6 to prevent the test device 5 from being inserted into the tray rotated 180 degrees from its proper orientation, which would undesirably result in the points 12 picking up test solutions from the wrong reservoirs 33. The formations 34 protrude from opposite sides of the handle 6 and are positioned such that they will engage the upper ends of the guide tabs 31 if a user attempts to insert the test device 5 wrong-end-to.
Referring to FIG. 4, the system may further comprise an adhesive-backed label 400 placed onto a lid or cover 21 that preferably forms an airtight seal when placed over the tray 30. Trays covered with lids 21 can be stacked to save space in refrigerators used to store the trays when they have been filled with skin test solutions and are not in use.
A shortcoming of the system described above is that test solution can be spilled from the reservoirs when the tray is bumped, otherwise moved abruptly, tilted onto its side, and the like.
Other conventional systems include capped reservoirs. For instance, FIG. 5 depicts a system available from Panatrex, Inc. of Placentia, Calif. Referring to FIG. 6, the Panatrex system includes multiple wells 600 and well lids 602. The manufacturer typically places well lids 602 onto wells 600 individually. This is an undesirably time-consuming process, which, of course, produces a corresponding undesirable manufacturing-cost component. Referring again to FIG. 5, the consumer, a healthcare professional, must insert each of the assembled well-and-lid combinations individually into a corresponding hole 502 in the reservoir-holding tray 500. Closure caps 504, which are located on the test device limbs, rest on a circular ridge 604 (FIG. 6) of each lid 602. In use, however, test solutions tend to undesirably accumulate around the well openings and ultimately adhere to the test device""s closure caps 504 in systems of the type shown in FIG. 5.
Cost and ease and speed of use are important factors considered by healthcare professionals when they are deciding which allergy skin test system to use. A need, therefore, exists in the prior art for a cost-effective pre-assembled skin-test system having capped reservoirs that overcomes the foregoing shortcomings of prior art multi-site skin-test systems.
In accordance with an illustrative embodiment of the invention, a multi-site allergy-skin-testing system includes a tray with reservoirs having an upwardly facing ledge surface. The ledge extends outwardly from an inner surface of an upper portion of the reservoirs. A bottom downwardly facing surface of each reservoir cap is adapted to rest on the upwardly facing ledge surface of the reservoirs. The upper portion of each reservoir is preferably adapted to receive a reservoir cap so that a relatively tight fit is achieved between the inserted reservoir caps and the upper portion of the reservoirs. The tight fit between the upper portion of the reservoirs and the reservoir caps advantageously eliminates the need for time-consuming and expensive manufacturing processes, such as ultrasonically welding the caps to the reservoirs.
The system also comprises a strip of interconnected reservoir caps. The caps of a strip are interconnected with one another via connection members. Each reservoir cap includes an upper surface and a tapered surface extending from the upper surface toward a lower surface, thereby defining a generally conically shaped depression having a circular hole at the bottom. The generally conically shaped depression and circular hole are collectively referred to herein as a tapered bore. The tapered bore preferably extends downwardly approximately the same distance as the height of a side surface of a reservoir cap.
The outer side surfaces of the caps are preferably adapted to fight tightly within the inside surfaces of corresponding upper portions of the reservoirs. The outer side surface of each cap preferably includes a slight draft or taper. Each of the upper portions of the reservoirs also preferably has a slight draft or taper corresponding to the slight draft or taper of the outer surface of each of the caps. The lower portion of the outside surface of each side of the caps preferably includes a beveled surface. A strip of caps having such beveled surfaces may advantageously be set in place by hand such that substantially only the beveled surfaces are inserted into the upper portions of the reservoirs. A machine, such as a pneumatic machine, may then be used to press the strip of caps into the reservoirs substantially simultaneously so that the top surfaces of the caps are substantially flush with the top surface of the tray. This process is significantly less time-consuming and significantly more cost-effective than inserting reservoir caps individually, and it results in healthcare professionals receiving a fully assembled product.
The tapered surfaces of the reservoir caps advantageously prevent skin-test solutions from splashing out of the reservoirs when the tray is moved abruptly. When inserted into the reservoirs, test device shafts partially close the reservoir cap holes, thereby preventing skin-test solutions from coming out of the reservoirs. When the tray, with strips of reservoir caps inserted into the tray, is tilted, even onto its side, test solutions will not come out of their wells because of the capillary attraction between the shaft and the circumference of the reservoir-cap holes. In this manner, test solutions accumulating around well openings and ultimately adhering to the test devices is advantageously avoided.
A guidance system cooperates with the tapered surface of the reservoir caps to provide additional clearance space for the pointed ends of the test device as the pointed ends are lowered into the reservoirs.
The system may further include a lid for the tray. The inside surface of the top of the lid may have a downwardly extending ridge. The downwardly extending ridge, cooperates with upright parallel tabs of the guidance system to prevent a user from putting the lid on top of tray rotated 180 degrees from its proper orientation, or, in other words, with the lid""s front and back sides reversed. The ridge also holds the test devices in place on the tray so that the shafts stay in position to serve as partial closures for the reservoir-cap holes.
A method, in accordance with an illustrative embodiment of the invention, of using a multi-site skin-testing system may include: removing a tray having pre-installed reservoir caps, each cap having a hole, from the tray""s packaging; at least partially filling the capped reservoirs with allergenic extract; inserting the shafts of a skin test device into the capped reservoirs so that the test device""s shafts partially close the reservoir cap holes; and performing a multi-site skin test using the test device without having to insert caps onto or into the reservoirs. The shafts of a second sterile skin test device may then be inserted into the capped reservoirs so that the second test device""s shafts partially close the reservoir cap holes. A lid, having a downwardly extending ridge, may then be placed onto the tray to hold the test device shafts in place in the reservoir-cap holes during transporting and storage.